It's a little soon to be feeding them anything for the purpose of feeding them solids but juice isn't harmful per se, kwim? I just like the idea of something a little more...natural? than corn syrup. I mean, at least it offers a little fiber and a little B6 whereas corn syrup offers nothing. Plus it has 30mgs of sodium which is something little ones definitely don't need.
I am BF and supplementing with formula. My LO had the same problem (it had been 6 days with no BM at all...was passing gas and just seemed completely uncomfortable - grunting and straining - all for nothing to come out) and my dr. recommended 1 oz of prune juice and 1 oz of formula mixed. No kidding...5 minutes after he finished the bottle, blowout! Cleared his little system and he felt SOOOOO much better!!
My DD is 6 weeks and has bathroom issues, my pediatrician told me to give her 1oz prune or pear juice mixed with 1oz water. Gerber makes both which seem to help.
Re: Karo syrup for constipation.